[Media Router] Custom Controls 1 - Add MediaStatus, MediaRouteController, and mojo interfaces

chrome/browser/media/router/mojo/media_route_controller.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/media/router/mojo/media_route_controller.h"
+
+#include <utility>
+
+namespace media_router {
+
+MediaRouteController::Observer::Observer(
+    scoped_refptr<MediaRouteController> controller)
+    : controller_(std::move(controller)) {
+  controller_->AddObserver(this);
+}
+
+MediaRouteController::Observer::~Observer() {
+  if (controller_)
+    controller_->RemoveObserver(this);
+}
+
+void MediaRouteController::Observer::InvalidateController() {
+  controller_ = nullptr;

[imcheng, 2017/03/21 21:19:58]

Should we call RemoveObserver here to be safe?

[takumif, 2017/03/21 22:59:49]

RemoveObserver() here will be necessary if the controller doesn't get deleted
after InvalidateController() calls for some reason. ObserverList allows removal
of observers during iteration, so I'll add RemoveObserver() here.

We also don't have to worry about InvalidateController() getting called twice,
since only MediaRouteController can call it.

+  OnControllerInvalidated();
+}
+
+void MediaRouteController::Observer::OnControllerInvalidated() {}
+
+MediaRouteController::MediaRouteController(
+    const MediaRoute::Id& route_id,
+    mojom::MediaControllerPtr media_controller)
+    : route_id_(route_id), media_controller_(std::move(media_controller)) {
+  DCHECK(media_controller_.is_bound());
+  media_controller_.set_connection_error_handler(
+      base::Bind(&MediaRouteController::Invalidate, base::Unretained(this)));
+}
+
+void MediaRouteController::Play() {
+  media_controller_->Play();
+}
+
+void MediaRouteController::Pause() {
+  media_controller_->Pause();
+}
+
+void MediaRouteController::Seek(base::TimeDelta time) {
+  media_controller_->Seek(time);
+}
+
+void MediaRouteController::SetMute(bool mute) {
+  media_controller_->SetMute(mute);
+}
+
+void MediaRouteController::SetVolume(float volume) {
+  media_controller_->SetVolume(volume);
+}
+
+void MediaRouteController::OnMediaStatusUpdated(const MediaStatus& status) {
+  for (Observer& observer : observers_)
+    observer.OnMediaStatusUpdated(status);
+}
+
+void MediaRouteController::Invalidate() {
+  for (Observer& observer : observers_)
+    observer.InvalidateController();
+  // |this| is deleted here!
+}
+
+MediaRouteController::~MediaRouteController() {}
+
+void MediaRouteController::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void MediaRouteController::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+}  // namespace media_router